Power supply apparatuses are essential for many electronic appliances and information products. Referring to FIG. 1, a schematic perspective view of an active heat-dissipating type of power supply apparatus is illustrated. The power supply apparatus 1 of FIG. 1 comprises a casing 11 (as indicated in the dotted line), plural electronic components 12, a power input device 13 and a power output device 14. The power input device 13 is an electronic connector such as a power socket. By plugging a plug of a power cable into the power socket 13, an AC voltage is transmitted from an external power source to the power supply apparatus 1. The AC voltage transmitted from the external power source is converted by the electronic components 12 into a regulated DC output voltage, which is transmitted to an electronic device through the power output device 14. During operation, the electronic components 12 may generate energy in the form of heat, and thus the space within the casing 11 is warmed up. If the power supply apparatus 1 fails to transfer enough heat to the ambient air, the elevated operating temperature may result in damage of the electronic components, a breakdown of the whole power supply apparatus 1 or reduced power conversion efficiency. For removing the heat, by forced convection, one or more fans 15 are used to either inhale the ambient air to cool the electronic components or exhaust the hot air to remove heat.
Please refer to FIG. 1 again. The ambient air is inhaled by the fan 15 into the space within the casing 11. The inhaled air is then conducted to the electronic components 12 to partially remove the heat generated from the electronic components 12. At the same time, a hot air is exhausted to the surroundings through an outlet (not shown). Since the hot air may conduct heat to the power input device 13, a portion of heat is accumulated on the power input device 13 due to a large thermal resistance thereof. As the power supply apparatus 1 is developed toward minimization and high power, the electronic components 12 may generate more heat. In addition, the current passing through the conductive terminals of the power input device 13 is also increased and thus the power input device 13 may generate more heat per se. For complying with safety regulations, it is important to dissipate heat away the power input device 13.
Moreover, according to an international standard safety temperature regulation, the operating temperature of the power input device 13 needs to be below such as 70° C. Nowadays, with development of diversified electronic devices, more and more electronic components 12 are loaded in the power supply apparatus 1. With increasing integration of integrated circuits, the power consumption of the power supply apparatus 1 is largely increased. As previously described, the heat generated from the electronic components 12 may influence the temperature of the power input device 13. Generally, for preventing damage from high temperature, the electronic components 12 are made of high-temperature resistant material, which may withstand a high temperature such as 110˜150° C. If the electronic components 12 are operated at such a high temperature, the operating temperature of the power input device 13 may exceed the acceptable value such as 70° C.
For a purpose of increasing integration of the electronic components 12, it is necessary to provide a heat-dissipating mechanism for removing heat from the power input device 13.